Human Endogenous Metabolite

Treatment with L-DABA results in 43.4% reduction of tumor growth. L-DABA is a more effective inhibitor of GABA transaminase in vivo than in vitro .

The tumor cells are irreversibly and totally damaged by incubation with 10 mM L-2,4-Diaminobutyric acid for 24 h at 37°C. The cell-destructive effect by L-DABA is probably due to an osmotic lysis induced by the non-saturated intracellular accumulation of L-DABA. The harmful effect of L-DABA could be abolished by concomitant incubation with L-alanine and L-methionine. Kinetic studies indicates that L-DABA is a non-linear, non-competitive inhibitor of GABA transaminase activity. The L-DABA-induced elevation of GABA levels parallels the inhibition of GABA transaminase activity. L-2,4-Diaminobutyric acid, an amino acid analogue, produceS a cytolytic effect with a human glioma cell line, SKMG-1, and normal human fibroblasts. The concentrations of L-DABA necessary to reduce the cell count to 50% of control following a 24-h incubation at 37°C are 12.5 mM for the human fibroblasts and 20 mM for the glioma cell line.

L-DABA (L-2,4-Diaminobutyric acid)是GABA转氨酶的弱抑制剂，IC50 值大于500 μM。在体内和体外具有抗肿瘤活性。